Anime: Canaan
Genre: TPS/Character Action
System: Any 3D-capable system.
Developer: Platinum
I always thought Canaan would make for a great game. Since the best thing about Canaan is her nutso agility combined with freakish accuracy, I think you have to set in an open world or at least open arenas to get the most out of her crazy movement abilities. Though I'm billing this as at least half third-person shooter, the actual aiming of Canaan's guns could be almost automated for all I care. The most important thing to nail is her free-flowing movement. Zipping around the kill arena targeting enemies and avoiding attacks to activate slow-time and build your combos like a long range Bayonetta is the name of the game, not hiding behind cover, aiming down sights, and pulling off pixel perfect headshots through trial and error. You are Canaan, therefore you should feel like badass from the word go. The only question should be what level of badass you can achieve and how stylish you will look while doing it.
Given that the combat I'm envisioning is a combination of Vanquish, DMC, and Platinum's Ninja Turtles game (only, like, good) my choice for developer is obvious. Using Canaan's synesthesia as an always-on visual overlay would also make for a really interesting game mechanic and artstyle-choice--effortlessly alerting players to enemies, allies, and quest opportunities, NPC emotional states, and, from a purely visual standpoint, providing the game with a lot of color and a distinct look.
I'm also interested in seeing a "perfect" conversion of an anime's visual style in something other than a fighting game. Heavy use of LOD recommended.